pf1e-simulator/tests/test_weapon_selection.py

"""Explicit attacking-weapon selection (Package U5d).

``attack`` and ``full_attack`` accept ``Action.weapon_id`` — the id of one of
the attacker's weapons. With it the engine strikes with THAT weapon instead of
the ``weapon_for`` auto-selection; a choice that is unknown, destroyed,
stolen, dropped, or unable to strike the target (out of reach / no line of
effect) is rejected with ``weapon_unavailable`` and no attack is made (a
BROKEN melee weapon stays selectable — CRB "Broken" makes it usable at -2).
Without it, the auto-selection and the full-attack mechanics are
byte-identical to before.
"""
from __future__ import annotations

from collections.abc import Callable

from pf1e_simulator.combat import (
    ACTION_RESULT_REASONS,
    Action,
    ActionResult,
    CombatantState,
    CombatEngine,
)
from pf1e_simulator.dice import parse_dice
from pf1e_simulator.grid import Grid
from pf1e_simulator.map import MapSpec, TerrainType
from pf1e_simulator.models import (
    AbilityScores,
    ACProfile,
    AttackSpec,
    Combatant,
    DamageComponent,
    Saves,
)
from pf1e_simulator.rng import ScriptedRng
from tests.test_observation_enriched import make_grid, make_state

PolicyFn = Callable[[CombatEngine, CombatantState], tuple[Action, ...]]

_WAIT: tuple[Action, ...] = (Action(kind="wait"),)


def _sword(
    id_: str, name: str, attack_bonus: int, *, reach_ft: int = 5
) -> AttackSpec:
    return AttackSpec(
        id=id_,
        name=name,
        kind="melee",
        attack_bonus=attack_bonus,
        reach_ft=reach_ft,
        damage=[DamageComponent(formula=parse_dice("1d6"), types=["slashing"])],
    )


def _combatant(id_: str, attacks: list[AttackSpec], *, initiative_mod: int = 0) -> Combatant:
    return Combatant(
        id=id_,
        name=id_,
        level=1,
        abilities=AbilityScores(
            str_score=10, dex_score=10, con_score=10,
            int_score=10, wis_score=10, cha_score=10,
        ),
        ac=ACProfile(total=10, touch=10, flat_footed=10),
        bab=1,
        initiative_mod=initiative_mod,
        speed_land_ft=30,
        hp_max=100,
        saves=Saves(fort=0, ref=0, will=0),
        attacks=attacks,
    )


# Hero's auto-selected weapon is "longsword" (first usable); "shortsword" is
# the explicit alternative with a lower bonus — the transcript distinguishes
# them by name and by the attack bonus.
def _two_swords() -> list[AttackSpec]:
    return [_sword("hero-long", "longsword", 5), _sword("hero-short", "shortsword", 2)]


def _duel(
    rng: list[int],
    *,
    hero_attacks: list[AttackSpec] | None = None,
    foe_pos: tuple[int, int] = (1, 2),
    grid: Grid | None = None,
) -> tuple[CombatEngine, CombatantState, CombatantState]:
    """hero at (1, 1) vs foe; scripted rolls only — no run(), no initiative."""
    hero = make_state(
        _combatant("hero", hero_attacks or _two_swords()), "players", (1, 1)
    )
    foe = make_state(
        _combatant("foe", [_sword("foe-w", "short sword", 5)]), "monsters", foe_pos
    )
    engine = CombatEngine(ScriptedRng(rng), grid or make_grid(), [hero, foe])
    return engine, hero, foe


# ── (a) the chosen weapon is the one that swings ──────────────────────────────


def test_attack_uses_the_explicitly_chosen_weapon() -> None:
    # d20 10 + 2 (shortsword) = 12 vs AC 10 -> HIT for 3; the auto-selected
    # longsword (+5) must NOT be the one swinging.
    eng, hero, foe = _duel([10, 3])
    result = eng._execute(
        hero, Action(kind="attack", target_id="foe", weapon_id="hero-short")
    )
    assert result == ActionResult(kind="attack", ok=True, reason="ok")
    line = eng._transcript[-1]
    assert "shortsword vs foe d20=10+2=12 AC 10 -> HIT 3 damage (100->97)" in line
    assert "longsword" not in line
    assert foe.hp == 97


def test_full_attack_uses_only_the_chosen_weapon() -> None:
    # Auto full_attack swings BOTH melee weapons (multi-weapon melee); with an
    # explicit choice only the shortsword swings.
    eng, hero, _foe = _duel([10, 3])
    result = eng._execute(
        hero, Action(kind="full_attack", target_id="foe", weapon_id="hero-short")
    )
    assert result == ActionResult(kind="full_attack", ok=True, reason="ok")
    joined = "\n".join(eng._transcript)
    assert "shortsword vs foe" in joined
    assert "longsword" not in joined


def test_full_attack_without_choice_still_swings_all_melee_weapons() -> None:
    eng, hero, _foe = _duel([10, 3, 10, 3])
    result = eng._execute(hero, Action(kind="full_attack", target_id="foe"))
    assert result == ActionResult(kind="full_attack", ok=True, reason="ok")
    joined = "\n".join(eng._transcript)
    assert "longsword vs foe d20=10+5=15" in joined
    assert "shortsword vs foe d20=10+2=12" in joined


# ── (b) broken / destroyed weapon selection ──────────────────────────────────


def test_attack_with_broken_weapon_is_usable() -> None:
    # CRB "Broken": a broken weapon is still usable — at -2 on attack and
    # damage. The explicit choice is accepted: d20 10 + 2 - 2 = 10 vs AC 10
    # -> HIT for 3 - 2 = 1 damage.
    eng, hero, foe = _duel([10, 3])
    hero.weapon_broken.add("hero-short")
    result = eng._execute(
        hero, Action(kind="attack", target_id="foe", weapon_id="hero-short")
    )
    assert result == ActionResult(kind="attack", ok=True, reason="ok")
    assert "shortsword vs foe d20=10+2=10 AC 10 -> HIT 1 damage" in eng._transcript[-1]
    assert foe.hp == 99


def test_attack_with_destroyed_weapon_is_rejected() -> None:
    # A destroyed weapon (hp <= 0, CRB "Smashing an Object": "ruined") is
    # unusable: the explicit choice is rejected, no roll consumed.
    eng, hero, foe = _duel([])  # empty script: any roll would raise
    hero.weapon_destroyed.add("hero-short")
    result = eng._execute(
        hero, Action(kind="attack", target_id="foe", weapon_id="hero-short")
    )
    assert result == ActionResult(
        kind="attack", ok=False, reason="weapon_unavailable"
    )
    assert any("attack rejected (weapon_unavailable)" in line for line in eng._transcript)
    assert foe.hp == 100


def test_full_attack_with_destroyed_weapon_is_rejected() -> None:
    eng, hero, foe = _duel([])
    hero.weapon_destroyed.add("hero-short")
    result = eng._execute(
        hero, Action(kind="full_attack", target_id="foe", weapon_id="hero-short")
    )
    assert result == ActionResult(
        kind="full_attack", ok=False, reason="weapon_unavailable"
    )
    assert foe.hp == 100


# ── (c) stolen weapon → weapon_unavailable ───────────────────────────────────


def test_attack_with_stolen_weapon_is_rejected() -> None:
    eng, hero, foe = _duel([])
    hero.weapon_stolen.add("hero-long")
    result = eng._execute(
        hero, Action(kind="attack", target_id="foe", weapon_id="hero-long")
    )
    assert result == ActionResult(
        kind="attack", ok=False, reason="weapon_unavailable"
    )
    assert foe.hp == 100


# ── (d) unknown weapon id → weapon_unavailable ───────────────────────────────


def test_attack_with_unknown_weapon_id_is_rejected() -> None:
    eng, hero, foe = _duel([])
    result = eng._execute(
        hero, Action(kind="attack", target_id="foe", weapon_id="ghost-blade")
    )
    assert result == ActionResult(
        kind="attack", ok=False, reason="weapon_unavailable"
    )
    assert any("attack rejected (weapon_unavailable)" in line for line in eng._transcript)
    assert foe.hp == 100


def test_weapon_unavailable_is_in_the_reason_vocabulary() -> None:
    assert "weapon_unavailable" in ACTION_RESULT_REASONS


# ── (e) chosen weapon cannot strike the target → weapon_unavailable ──────────


def test_attack_with_out_of_reach_weapon_is_rejected() -> None:
    # Foe 4 cells away: the chosen melee weapon cannot reach, even though
    # some other weapon might (here none can — but the choice is what fails).
    eng, hero, foe = _duel([], foe_pos=(1, 5))
    result = eng._execute(
        hero, Action(kind="attack", target_id="foe", weapon_id="hero-long")
    )
    assert result == ActionResult(
        kind="attack", ok=False, reason="weapon_unavailable"
    )
    assert foe.hp == 100


def test_attack_with_no_line_of_effect_weapon_is_rejected() -> None:
    # Wall at (1,1) between hero (1,0) and foe (1,2): the longspear (10 ft
    # reach) is IN range but has no line of effect -> weapon_unavailable.
    rows = ["." * 8, ".#." + "." * 5] + ["." * 8] * 6
    legend = {
        ".": TerrainType(type="floor", move_cost=1),
        "#": TerrainType(type="wall", move_cost=None, blocks_los=True),
    }
    grid = Grid.from_spec(MapSpec(name="wall", terrain=tuple(rows), legend=legend))
    hero_spear = [_sword("hero-pike", "longspear", 5, reach_ft=10)]
    eng, hero, foe = _duel(
        [], hero_attacks=hero_spear, foe_pos=(1, 2), grid=grid
    )
    hero.pos = (1, 0)
    result = eng._execute(
        hero, Action(kind="attack", target_id="foe", weapon_id="hero-pike")
    )
    assert result == ActionResult(
        kind="attack", ok=False, reason="weapon_unavailable"
    )
    assert foe.hp == 100


# ── (f) no weapon_id → identical to today's auto-selection ───────────────────


def test_explicit_auto_equivalent_weapon_matches_no_choice() -> None:
    # Same scripted scenario with weapon_id=None and with the weapon the
    # auto-selection would pick anyway: transcripts must be byte-identical.
    eng_a, hero_a, _foe_a = _duel([10, 3, 10, 3])
    res_a = eng_a._execute(hero_a, Action(kind="attack", target_id="foe"))
    eng_b, hero_b, _foe_b = _duel([10, 3, 10, 3])
    res_b = eng_b._execute(
        hero_b, Action(kind="attack", target_id="foe", weapon_id="hero-long")
    )
    assert res_a == res_b == ActionResult(kind="attack", ok=True, reason="ok")
    assert eng_a._transcript == eng_b._transcript
    assert "longsword vs foe d20=10+5=15" in eng_a._transcript[-1]


def test_no_choice_full_attack_transcript_is_unchanged() -> None:
    # Policy-driven full run: the auto full_attack transcript keeps its exact
    # shape (both melee weapons, in usable_attacks() order).
    def policy(_engine: CombatEngine, state: CombatantState) -> tuple[Action, ...]:
        if state.combatant.id == "hero":
            return (Action(kind="full_attack", target_id="foe"),)
        return _WAIT

    hero = make_state(_combatant("hero", _two_swords(), initiative_mod=2), "players", (1, 1))
    foe = make_state(
        _combatant("foe", [_sword("foe-w", "short sword", 5)]), "monsters", (1, 2)
    )
    # initiative: hero d20 10 (+2), foe d20 5; hero full_attack: hit+damage, hit+damage.
    eng = CombatEngine(
        ScriptedRng([10, 5, 10, 3, 10, 3]), make_grid(), [hero, foe],
        policy=policy, round_cap=1,
    )
    t = eng.run().transcript
    assert "round 1 hero: longsword vs foe d20=10+5=15 AC 10 -> HIT 3 damage (100->97)" in t
    assert "round 1 hero: shortsword vs foe d20=10+2=12 AC 10 -> HIT 3 damage (97->94)" in t
    assert hero.last_action_results == [
        ActionResult(kind="full_attack", ok=True, reason="ok")
    ]